JensKrumsieck/ChemSharp

using System.Text;
using ChemSharp.Export;
using ChemSharp.Extensions;

namespace ChemSharp.Spectroscopy.Export;

public class CSVExporter : AbstractSpectrumExporter
{
    /// <summary>
    ///     CSV Separator
    /// </summary>
    private char Separator = ',';

    public static void Export(Spectrum spc, string filename, char separator,
                              SpectrumExportFlags flags = SpectrumExportFlags.Experimental)
    {
        var exporter = new CSVExporter {Separator = separator, Flags = flags};
        using var stream = File.Create(filename);
        exporter.Export(spc, stream);
    }

    public static string ExportToString(Spectrum spc, char separator,
                                        SpectrumExportFlags flags = SpectrumExportFlags.Experimental)
    {
        var exp = flags.HasFlag(SpectrumExportFlags.Experimental);
        var deriv = flags.HasFlag(SpectrumExportFlags.Derivative);
        var integral = flags.HasFlag(SpectrumExportFlags.Integral);

        var csv = new StringBuilder();
        csv.AppendLine(spc.Title);
        var xTitle = $"{spc.XQuantity}/{spc.XUnit}{separator}";
        csv.AppendLine($"{xTitle}{separator}" +
                       $"{(deriv ? $"{xTitle}Derivative" + separator : "")}" +
                       $"{(integral ? $"{xTitle}Integral" + separator : "")}");

        for (var i = 0; i < spc.XYData.Count; i++)
        {
            var line = new StringBuilder();
            if (exp)
            {
                line.Append(spc.XYData[i].X.ToInvariantString() + separator);
                line.Append(spc.XYData[i].Y.ToInvariantString() + separator);
            }

            if (deriv)
            {
                line.Append(spc.Derivative[i].X.ToInvariantString() + separator);
                line.Append(spc.Derivative[i].Y.ToInvariantString() + separator);
            }

            if (integral)
            {
                line.Append(spc.Integral[i].X.ToInvariantString() + separator);
                line.Append(spc.Integral[i].Y.ToInvariantString() + separator);
            }

            csv.AppendLine(line.ToString());
        }

        return csv.ToString();
    }


    protected override void Export(IExportable exportable, Stream stream)
    {
        base.Export(exportable, stream);
        using var sw = new StreamWriter(stream);
        sw.Write(ExportToString(Spectrum, Separator, Flags));
    }
}